1. Field of the Invention
The present invention relates to a machine designed to decorticate, i.e. separate, the bast fibers comprising the outer bark of kenaf, jute, or similar stalks from the inner core thereof with minimum damage to the bast fibers. In particular, the invention relates to a unique arrangement and operating speed of sets of feed rollers which crush and split the bast fiber longitudinally and break the core into short segments, and beater rollers to loosen and separate the core pieces from the bast fibers.
2. Discussion of the Background
A decorticating machine is described in U.S. Pat. No. 2,719,332 which includes feed rollers adapted to feed the stalks toward a backing plate which has a surface which cooperates with the sharp edges on the blades or fins of a beater roller to cause the cores of the stalks to disintegrate. One or more additional beater rollers are provided for beating the stalks to remove the broken core pieces and other undesirable material. Another decorticating apparatus is described in U.S. Pat. No. 442,735. The apparatus disclosed in the '735 patent includes a plurality of feed rollers some of which are smooth and some of which are corrugated. A knife is positioned at the output side of the most downstream set of feed rollers to split the stalk longitudinally and direct one half of the split stalk to one set of beater rollers and the other half of the stalk to another set of beater rollers. In both the '332 and '735 patents, the rollers used for beating the stalks to remove the broken core pieces are driven at a higher speed than the feed rollers. Neither of said patents provides for additional sets of feed rollers to further crush the stalks and break up the core pieces after the stalks pass through a set of beater rolls nor does either patent provide for driving the upper roll of a set of beater rolls at a different speed than the lower beater roll. In addition, there is no discussion in either patent with respect to the rotational or linear (i.e., tangential) speed at which any of the rollers should be driven or that there is any correlation between the speed of operation of the various rollers and the amount of core which is removed from the bast fibers as the stalks pass through the machine.